Nine people were arrested in raids on two West Bank outposts in the wake of a firebombing that killed a Palestinian man and his 18-month-old toddler.

Israel has intensified its crackdown on Jewish extremists in the wake of a firebombing that killed a Palestinian man and his 18-month-old toddler, arresting nine people suspected of involvement in extremist activities on Sunday morning.

Two people were arrested in Adei Ad, an outpost of around 20 families close to the West Bank village of Douma where the July 31 firebombing occurred, and seven others were taken into custody in raids on Baladim, an outpost in the northern part of the West Bank.

Both communities were built without permission from Israeli authorities, and are known for their hardline settler populations. In January, settlers from Adei Ad threw stones at US diplomats who were inspecting damage at a grove of Palestinian-owned olive trees near the outpost.

The spate of arrests follows the death on Saturday of 32-year-old Saad Dawabsha, who sustained second degree burns on more than 80 percent of his body in the July 31 attack that authorities believe was committed by Jewish extremists. Dawabsha's 18-month old son died at the scene, and his wife and four-year-old son remain in a critical condition.

Last Sunday, in response to the firebombing — a so-called "price-tag" attack committed as revenge for actions taken against settlers by the Israeli government — Israeli Defense Minister Moshe Ya'alon approved the use of administrative detention orders, a form of indefinite incarceration without trial, against Jewish extremists.

Three men, all in their early to mid-20s, have been sentenced to six months in jail under the orders. Among them is Meir Ettinger, the grandson of the late Rabbi Meir Kahane, an extremist Israeli-American right winger, and Eviatar Slonim, who was previously questioned in relation to a separate arson attack on a Palestinian home in the South Hebron Hills. Ettinger has been accused of heading an underground network of Jewish terror cells that attacked Palestinian homes and Christian holy sites. Both men were subject to restraining orders that banned them from entering Jerusalem and the West Bank.

Responding to the crackdown, Honenu, a right-wing legal aid organization, said that Israeli police had "joined the atmosphere of incitement" against settlers, and suggested that a "witch hunt" was underway. The group, which represents Ettinger, also claimed that their client was subjected to torture, including "sleep deprivation," and "shaking… during interrogation."

Administrative detention has long been used to hold Palestinian terror suspects, but Israeli security officials have said the government previously refused repeated requests to use to the measure to imprison known Jewish extremists.

According to Addammeer, a Ramallah-based prisoner advocacy group, around 400 Palestinians are held under administrative detention orders, mostly for security related offenses that range from stone-throwing to plotting terror attacks.

Israeli security services have not yet commented on whether any of the Jewish extremists that have been arrested are suspected of direct involvement in the attack that killed Dawabsha and his son.